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/* SPDX-License-Identifier: BSD-2-Clause */
/*
* This file implements a benchmark timer using a TX39 timer.
*
* NOTE: On the simulator, the count directly reflects instructions.
*
* COPYRIGHT (c) 1989-2000.
* On-Line Applications Research Corporation (OAR).
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <assert.h>
#include <bsp.h>
#include <rtems/btimer.h>
bool benchmark_timer_find_average_overhead;
void benchmark_timer_initialize(void)
{
/*
* Programming the compare register as the maximum value should let
* it run long enough and accurate enough not to require an interrupt.
* but if it ever does generate an interrupt, we will simply fault.
*
* NOTE: This is similar to the clock driver initialization
* with the exception that the divider is disabled and
* the compare register is set to the maximum value.
*/
TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_TCR, 0x20 );
TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_CCDR, 0x3 );
TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_TRR, 0x0 );
TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_CPRA, 0xFFFFFFFF );
TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_TISR, 0x00 );
TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_ITMR, 0x0001 );
TX3904_TIMER_WRITE( TX3904_TIMER1_BASE, TX3904_TIMER_TCR, 0xe0 );
}
#define AVG_OVERHEAD 0 /* It typically takes N instructions */
/* to start/stop the timer. */
#define LEAST_VALID 1 /* Don't trust a value lower than this */
/* tx39 simulator can count instructions. :) */
benchmark_timer_t benchmark_timer_read(void)
{
uint32_t total;
total = TX3904_TIMER_READ( TX3904_TIMER1_BASE, TX3904_TIMER_TRR );
if ( benchmark_timer_find_average_overhead == true )
return total; /* in one microsecond units */
if ( total < LEAST_VALID )
return 0; /* below timer resolution */
return total - AVG_OVERHEAD;
}
void benchmark_timer_disable_subtracting_average_overhead(
bool find_flag
)
{
benchmark_timer_find_average_overhead = find_flag;
}
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